TDS faulty reading, or... (1 Viewer)

[tmgrash]

I just replaced my RO membrane and DI resin about 2 weeks ago. My TDS reading (from the inline tds meter) says 12 tds after ro and 400+ after DI resin. After about 15mins of running it it drops to about 15 post di. I have heard of tds creep but this seem extreme, what are ya'lls thoughts? BTW the meter was showing 0 tds after di first day of install and I didnt really check again after that.

 

[tektite]

Swap the terminals of the TDS meter around and see if you still get the same readings. My TDS reads a little high right after I start up the RO/DI unit, but after 20-30 secs it drops to 0 post-DI.

 

[steveb]

I just replaced my RO membrane and DI resin about 2 weeks ago. My TDS reading (from the inline tds meter) says 12 tds after ro and 400+ after DI resin. After about 15mins of running it it drops to about 15 post di. I have heard of tds creep but this seem extreme, what are ya'lls thoughts? BTW the meter was showing 0 tds after di first day of install and I didnt really check again after that.

Its funny you should mention that. I'm having a very similar issue.

I replaced my 100gpd RO membrane with a 75 (and changed the restrictor) + added the 150gpd upgrade from BRS (2nd 75gpd membrane). I also replaced my sediment - 1 micron, carbon - 0.5 micron and DI resin. Post upgrade running 90psi on my booster pump I was getting 12 ppm TDS out of the RO and 14 ppm TDS out of the DI resin. After about an hour it dropped to 4ppm TDS out of the DI resin. I logged a call to BRS and they said either my DI resin had gone bad or my inline TDS meter was off. I will have to check it again when I make another batch of water.

 

[flexrac]

Steve: i find anytime you are running more than 75gpd on an RO in Houston you never get 0, atleast that is what i am finding. i had a 100gpd system that never to 0 after di, after talking to BFS, i switched to a 75gpd by swapping the restictor and now i get 0 tds. you could try using dual DI's, i had someone do it before and it worked,or upgrade your di to a larger canistor.
Travis, i'm not sure what's going on with yours, try what cat said and then my solution.

 

[steveb]

I used to get 0 tds from mine when it was 100gpd and before the filters wore out. It should get 0 tds now...

The 150gpd system is two 75gpd membranes hooked in series. The waste water from the first one is passed into the membrane of the the second one. The second one has the 75gpd restrictor. I think it has to do with either my TDS meter being out of wack or the DI resin. I'm fixing to run another batch and I will post the TDS readings.

 

[Ostentum]

I run a 90 gpd Spectrapure system, Travis we should have similar water since we are both in League City. I know that water incoming is around 175 TDS. Mine is 9 after RO and 0 after DI. I would check your actual TDS meter or get yourself a handheld one just as a safe check. I borrowed one from Dennis at FJW awhile back just to verify.

 

[reeftopia]

My problem is after the water sets a couple of days my number jumps up to about 90.

 

[steveb]

I just wanted to follow up. When I made another 20 gallon batch of water the TDS on the meter went to 0. I think the DI resin wasn't fully saturated at first. But oh man I do love the 150gpd upgrade with the pump It almost comes out in a fast dribble... :biglaugh:

 

[BigRick]

I run dual DI's and get 0 TDS. I get about 4-7 TDS coming out of the membrane

 

[Andy]

If you backwash membrane b/f you restart the "start up" high readings will go down quickly.

If you don't backwash you are sending high TDS into your DI thus wearing it out sooner

Also it cleans off RO membrane at the same time.

.02

 

[steveb]

Yeah I do backwash, well I did before with my single 100gpd membrane. I didn't when I did my 1st batch of water this time because the membranes where new (I ran water through them for an hour before sending the output to the DI resin). But now that I think about it I'm going to have to sit down and think about how I am going to backwash with the new config, two 75gpd membranes hooked in series (150 gpd BRS upgrade kit).